/*
 *  2ooM: The Master of Orion II Reverse Engineering Project
 *  Routines for rendering LBX images to a GdkPixbuf.
 *  Copyright (C) 2010 Nick Bowler
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <assert.h>
#include <gtk/gtk.h>

#include "render.h"
#include "image.h"

/* LBX images can have up to three palettes, with each superseding the last. */
struct lbx_colour palette_external[256];
struct lbx_colour palette_internal[256];
struct lbx_colour palette_override[256];

static inline unsigned scale6to8(unsigned x)
{
	assert(x <= 0x3f);

	return x*0xff / 0x3f;
}

static void get_colour(unsigned char index, unsigned char out[static 4])
{
	struct lbx_colour *colour;

	if (palette_override[index].active)
		colour = palette_override + index;
	else if (palette_internal[index].active)
		colour = palette_internal + index;
	else if (palette_external[index].active)
		colour = palette_external + index;
	else
		colour = &(struct lbx_colour) { .red = 0x3f, .blue = 0x3f };

	out[0] = scale6to8(colour->red);
	out[1] = scale6to8(colour->green);
	out[2] = scale6to8(colour->blue);
	out[3] = -1; /* opaque */
}

int render_to_pixbuf(struct lbx_image *image, GdkPixbuf *pixbuf, unsigned frame)
{
	unsigned char **framedata, **framemask, *outbuf;
	unsigned stride;

	assert(image->width  == gdk_pixbuf_get_width(pixbuf));
	assert(image->height == gdk_pixbuf_get_height(pixbuf));

	framedata = lbx_img_getframe(image, frame);
	g_return_val_if_fail(framedata, -1);
	framemask = lbx_img_getmask(image);

	outbuf = gdk_pixbuf_get_pixels(pixbuf);
	stride = gdk_pixbuf_get_rowstride(pixbuf);

	for (unsigned i = 0; i < image->height; i++) {
		unsigned char (*px)[4] = (void *)(outbuf + i*stride);

		for (unsigned j = 0; j < image->width; j++) {
			if (framemask[i][j])
				get_colour(framedata[i][j], px[j]);
			else
				px[j][3] = 0; /* transparent */
		}
	}

	return 0;
}